INHIBITORY LEFT ATRIAL INFLUENCES ON THE BAROREFLEX

左心房对压力反射的抑制性影响

• 批准号: 3358682
• 负责人: DAVID J RAMSAY
• 金额: $ 17.19万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1992-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3358682
• 关键词: adrenocorticotropic hormone; atrial natriuretic peptide; atrium; baroreceptors; blood volume; dogs; homeostasis; hormone regulation /control mechanism; hypotension; hypovolemia; intracardiac pressure; neurohormones; renin; secretion; thirst; vasopressins

The long-term objective of the proposed studies is to evaluate the contribution of low and high pressure baroreceptors in the neurohumoral responses to simulated hypovolemia. Reduction in venous return leads to stimulation of renin, vasopressin and ACTH secretion and to drinking. These mechanisms, together with the sympathetic nervous system stabilize blood pressure and act synergistically to return fluid balance to normal. The overall hypothesis is that unloading baroreceptors in the left atrium is essential for the expression of these neurohumoral responses to simulated hypovolemia. Differential changes in pressure will be achieved by graded constriction of cuffs placed around the thoracic portion of the inferior vena cava, pulmonary artery, ascending aorta and abdominal aorta proximal to the renal arteries. The hypothesis that increases in left atrial, rather than left ventricular, pressure inhibit vasopressin, renin and ACTH secretion and drinking when arterial blood pressure is reduced by ascending aortic cuff constriction will be tested. Techniques of maintenance of normal left atrial pressures and selective ventricular denervation during aortic constriction will be used. The effects of raised right atrial pressure on the neurohumoral response to arterial hypotension will be evaluated using pulmonary artery constriction. Inflation of a balloon in the pulmonary vein/left atrium junctional region will be used to assess the effects of increasing afferent discharge without release of atrial natriuretic factor (ANF), and compared with inflation of a balloon placed at the mitral valve orifice which increases afferent discharge and ANF release. It is anticipated that both left atrial baroreceptors and ANF contribute to the inhibition of renin, vasopressin and ACTH release and drinking when left atrial pressure increases. The contribution of the sympathetic nervous system to inhibition of renin secretion when left atrial pressure increases will be assessed by measurement of plasma epinephrine and measurement of renal nerve activity. Thus it is anticipated that the essential role of the left atrium in hormonal and thirst responses to simulated hypovolemia will be established and that the mechanism of these interactions will be elucidated.

拟议研究的长期目标是评估 低压和高压压力受体的贡献 神经肿瘤对模拟低血容量的反应。 减少 静脉回流会导致肾素，加压素和ACTH的刺激 分泌和喝酒。 这些机制以及 交感神经系统稳定血压并作用 协同恢复流体平衡至正常水平。 总体 假设是左心房中卸载的压力受体是 这些神经肿瘤反应的表达至关重要 模拟低血容量。 压力的差异将是 通过在胸腔周围放置的袖口的分级收缩来实现 下腔静脉，肺动脉的一部分，上升 主动脉和腹主动脉靠近肾动脉。 这 假设增加了左心而不是左侧的假设 心室，压力抑制加压素，肾素和ACTH分泌 当动脉血压降低时喝酒 主动脉袖子收缩将进行测试。 维护技术 正常的左心压和选择性心室 将使用主动脉收缩期间的神经化。 效果 对神经肿瘤反应的右心房压力升高 将使用肺动脉评估动脉低血压 收缩。 气球在肺静脉/左侧的通胀 中庭连接区域将用于评估 不释放房屋纳地尿药的传入排放量增加 因子（ANF），并与放置在 二尖瓣孔口增加传入排放和ANF 发布。 可以预期均留下心房的压力感受器和 ANF有助于抑制肾素，加压素和ACTH 剩下心房压力时释放和饮酒。 这 交感神经系统对抑制的贡献 肾脏分泌时左心房压力增加将是 通过测量血浆肾上腺素的测量和测量 肾神经活动。 因此，预计必不可少的 左心房在荷尔蒙和渴望中的作用 将建立模拟的低血容量，并确定机制 这些相互作用将被阐明。